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Code Issues Releases Activity

[DHT] Add delay right after waking sensor

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This commit is contained in:
TD-er
2022-07-31 09:53:54 +02:00
parent b10323cd30
commit 34cca83fd8
1 changed files with 26 additions and 13 deletions
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src/src/PluginStructs/P005_data_struct.cpp
+26 -13
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@@ -78,7 +78,8 @@ bool P005_data_struct::waitState(int state)
while (DIRECT_READ(reg, mask) != state)
{
if (usecTimeOutReached(timeout)) { return false; }
// delayMicroseconds(1);
// delayMicroseconds(1);
}
return true;
}
@@ -104,13 +105,25 @@ bool P005_data_struct::readDHT(struct EventStruct *event) {
case P005_SI7021: delayMicroseconds(500); break;
}
// Pull the pin high as we don't know how fast the DHT might pull it high if we just set the pin to input.
// The capacitance of the cable may delay this, but we need to make sure the logic level is high before we call waitState(0).
DIRECT_WRITE_HIGH(reg, mask); // Pull High
// Direct access functions cannot set the pull-up, or at least I have no clue where to set it.
// However the timing here is not really critical as the ESP is supposed to pull the pin high and then wait for the sensor to pull it low,
// high, low to signal the starting sequence.
pinMode(DHT_pin, INPUT_PULLUP);
{
const uint64_t moment_pull_high = getMicros64();
// Pull the pin high as we don't know how fast the DHT might pull it high if we just set the pin to input.
// The capacitance of the cable may delay this, but we need to make sure the logic level is high before we call waitState(0).
DIRECT_WRITE_HIGH(reg, mask); // Pull High
// Direct access functions cannot set the pull-up, or at least I have no clue where to set it.
// However the timing here is not really critical as the ESP is supposed to pull the pin high and then wait for the sensor to pull it
// low,
// high, low to signal the starting sequence.
pinMode(DHT_pin, INPUT_PULLUP);
// Wait for the signal to really be "high"
const uint64_t since_pull_high = usecPassedSince(moment_pull_high);
if (since_pull_high < 20) {
delayMicroseconds(20 - since_pull_high);
}
}
bool readingAborted = false;
uint8_t dht_dat[5];
@@ -122,7 +135,7 @@ bool P005_data_struct::readDHT(struct EventStruct *event) {
// Response from DHTxx: (N = 80 usec for DHT22)
// Low for N usec
// Hight for N usec
// Low for N usec
// Low for 50 usec
bool receive_start;
noInterrupts();
@@ -133,7 +146,7 @@ bool P005_data_struct::readDHT(struct EventStruct *event) {
uint64_t last_micros = getMicros64();
uint64_t prev_edge = last_micros;
for (i = 0; i < 5 && !readingAborted; i++)
for (i = 0; i < 5 && !readingAborted; ++i)
{
uint8_t timings[16] = { 0 };
@@ -143,10 +156,10 @@ bool P005_data_struct::readDHT(struct EventStruct *event) {
const int current_state = (t & 1);
// Wait till pin state has changed, or timeout.
while (DIRECT_READ(reg, mask) == (t & 1) && !readingAborted)
while (DIRECT_READ(reg, mask) == current_state && !readingAborted)
{
// Keep track of last microsecond the state had not yet changed.
// This way we are less dependent on any jitter caused by
// This way we are less dependent on any jitter caused by
// the delay call or rise times of the voltage on the pin.
last_micros = getMicros64();
@@ -155,7 +168,7 @@ bool P005_data_struct::readDHT(struct EventStruct *event) {
}
// Wait at least 1 usec or else we might be computing a lot of time diffs.
// delayMicroseconds(1);
// delayMicroseconds(1);
}
if (!readingAborted) {